Welded lattice girders



May 17, 1960 E. CVIKL 2,936,862

WELDED LATTICE GIRDERS Filed April 6. 1955 2 Sheets-Sheet 1 May 17, 1950E. CV|K| WELDED LATTICE GIRDERS 2 Sheets-Sheet 2 Filed April 6, 1955United States Patent O y WELDED LATTICE GIRDERS Ernst Cvikl, Homburg,Germany, assignor of one-half to Marcello Germani, Milan, ItalyApplication April 6, 1955, Serial No. 499,712 Claims priority,application Germany April 7, 1954 Claims. (Cl. 189-37) This inventionrelates to welded lattice girders of triangular cross-section, and anobject of the invention is to provide an improved girderA formed largelyof round steel rods and particularly suitable for use as a roof supportor rafter. o

According to the invention there is provided a welded lattice girder oftriangular cross-section with two round steel rods as upper chordmembers and a round steel rod as a lower chord member, characterised inthat the upper and lower chord members are interconnected byA tice-worksupports for roof rafters, in which the roof` battens or purlins must besecured by means of additional ridged sections or fastening means or thelike, the invention makes it possible to secure a wooden batten to theupper side of the lattice girder in a simple manner, so that the purlinscan be fastened to the batten by simple nailing as in a roof frame .ofwood.

From the point of view of technical production, the construction of thelattice girder according to the invention is very simple, as all thewelding Yzones are readily accessibleand can be effected as groove seamsand thus also from the point of view of welding technique can beproduced easily both with the use of the simpler apparatus and with thesmallest labour requirefor mass production. Further features of theinvention appear from the following description and are vset forth inthe claims.

The invention is illustrated by way of example in the accompanyingdrawings in which:

Figure 1 is a side view of a girder according vto the invention,

Figure 2 is a plan in the direction of the arrow II in Figure l,

Figure 3 is a section on the line III- III of Figure 2,

Figure 4 is a part sectional view of a roof construction employinggirders according to the invention,

Figures 5 and 6 show details to a larger scale of parts within thecircles IV and V of Figure 4,

Figure 7 is a side view of the roof construction, and

Figure 8 is a detail view to a larger scale of the part within thecircle VIII of Figure 7.

The illustrated girder consists largely of round steel rods andcomprises two upper chord members 1, a lower chord member 2, andlattice-work-like strut or vertical members 3 and stay members 4; inconsequence of the particular formation of the latter the girder has atriangular or V-shaped cross-section. The lower chord member 2 is benttowards the upper chord members 1 ments. The girder consequently is alsovery suitable atthe ends of the girder and the chord members areconnected together at each end by means of an angle piece 5 to whichthey are welded, the angle pieces 5 also serving for mounting means forsecuring the girder for example to a building structure and also at theridge when the girders serve as roof spars or rafters. The chord members1 and 2' and also the strut'members 3 and stay members 4 all consistingof round steel rods are all also connected together by means of welding.

As can be seen from Figure 3 in particular, the upper chord'members 1abut the outer edges of yan elongated isosceles triangle standing uponits point. The shape of the thus formed geometrical iigure'beingdetermined by the strut member 3. As will be seen from Figures 1 and 2,the lower ends of the vertical or strut member 3 are, at their points ofcontact with the lower chord member 2, arranged one in front of theother, which fact is of particular advantagefrom the point of weldingbecause in this way throat seam or llet welds can easily andsatisfactorily be employed. Y

Moreover, in view of the use of the double diagonal stay members 4 thenumber of welding positions is reduced in comparison with single stays;they can be bent in one working stage and simultaneously cut off at anangle with the tapering oi at their ends, whereby there is aiorded thepossibility of joining them by llet welds considered highly favorable inthe welding art.

The struts 4 have `in plan view (Figure 2) a Zfshaped form, withouthowever lying in a single plane, but as can be seen from Figures l and4, the limbs forming the diagonal stays are bent downwardly at equalangles indirection to the lower chord member 2 and lie one Vin each sideplane ofthe girder. Their connecting points For securing the girder atthe' ridge of a roof con-y nection, a piece of tube or sleeve 9 (Fig.2), equal in length to half the width of the girder is welded to-theangle piece 5. Secured, for e.g. by welding, to the angle piece 6 inthe central plane of the girder, is a securing lug 10 with an aperture11.

The formation of a roof assembly by means of girders according to theinvention is illustrated in particular in AFigure 4 in cross-section andin Figure 7 in side view.

The manner of securingthe girder to the building structure isillustrated by the detail in the circle VI of Figure 4 and isshown on alarger scale in Figure 6. A bearing block 12 is secured by means ofanchor bolts 13 to the building structure 14. The block' 12 serves forthe reception of the fastening luglt), ya bolt 15 being inserted andscrewed through the aperture 11 of the lug and likewise through anaperture in the bearing block 12. At the ridge (see in particular Figure5) the girders are simultaneously connected in pairs to form three jointstructures and at the same time all connected to the rafters or roofsupports'by means of a ridge tube 16 which is inserted through thesleeves 9. Through the one-sided or asymmetrical arrangement in eachcase of the sleeve 9 it is possible to employ a mass produced girder foralternative arrangement either on the right-hand or left-hand' side of aroof. is apparent in particular from Fig- Paiepied May 17, 1960l oneV ofa pair of girders which is nearer to the viewer, whereas the sleeve orhinge' portion '9b belongs to the opposite girder which is completelycoveredY from the view by the nist-mentioned girder. The battens 7arranged on the girders make possible the easy fastening of theroofrbattens or purlins 18 for the reception of the roof tiles or thelike (see in particular Figure 4). A wind brace 17 stiiens the thusproduced roof Structure against wind forces.

In addition to roof structures, in particular for small roofs withwooden battens or sheathing,sthe girders according to the invention aresuitable for every purpose in which it is desired to combine smallweight with highv loading and large width of span; moreover thesimplicity ofv the construction of the girders makes them particularlysuitable for mass production;

u LAY welded lattice girder of triangular cross section which comprisesin combination: an upper chord'having two longitudinally extending rodsof substantially circular cross section; a lower chord comprising asingle longitudinally extending rod of substantially circular crosssection; a plurality of strut members spacedlongitudinally along saidgirder, each of said strut members being formed of an integral rod andhaving the shape of a closed triangle with the tip of the trianglewelded to the lower chord and with the base of the triangle extendingtransverse to the longitudinal direction of the upper chordl and weldedthereto, said triangular strut members being located in planesrespectively arranged perpendicular to both said upper chordand saidlower chord; and a plurality of stay members alternating with said strutmembers, each stay member being formed of an integral rod comprising across piece transverse to the' longitudinal direction of the girder andwelded to the two rods of the upper chord intermediate two of saidstruts and also comprising two diagonal portions respectively extendingfrom the ends of said cross piece in opposite directions with regard tothe longitudinal direction of the girder, the free ends of said diagonalportions being welded to said lower chord at the tips of said twostruts.

2. A girder according to claim l, in which the two longitudinallyextending rods forming the upper chord have their bottom sides welded.to the top sides of the base of the triangle-shaped strut' members andto the top sides of the cross pieces of said stay members.

3. A welded lattice girder of triangulary cross section which comprisesinY combination: an upper chordhaving two longitudinally extending rodsof substantially circular cross section; a lower chord comprising asingle longi tudinally extending rod of substantially circular crosssection; a plurality of` strut members spaced longitudinally along saidgirder, each of said strut members being formed of an integral rod andhaving the shape of a closed triangle with the tip of the trianglewelded to the lower chord and with the base of the triangle extendingtransverse to the longitudinal direction of the upper chord and weldedthereto, said triangular strut members being located in planesrespectively arranged perpendic ular to both said upper chord and saidlower chord; a a plurality of stay members alternating with said strutmembers, each stay member being formed of an integral rod comprising across piece transverse to the longitudinal direction of the girder andwelded to the two rods o`f the upper chord intermediate two of saidstints and also comprising two diagonal'portions respectively extendingfrom the ends of said cross piece in opposite directions with regard tothe longitudinal direction of the girder, the free ends of said diagonalportions being welded to said lower chord at the tips of said twostruts, and two connecting members respectively arranged at the ends ofsaid girder and each respectively connecting the ends of said upperchord with the ends of said lower chord, one of lsaidconnectingme'mbe'rs being providedwith a hinge-like outwardly directedextension locatedr inV substantially the central longitudinal plane ofsaid girder and having a transverse bore therethrough and the otherconnecting member having connected thereto one tubular hinge portiononly extending from one side of said girder to substantially saidcentral longitudinal plane thereof.

4. A welded lattice girder of triangular cross section which comprisesin combination: an upper chord having two longitudinally extending rodsof substantially circular cross section; a lower chord comprising asingle longitudinally extending rod of substantially circular crosssection; a plurality of strut members spaced longitudinally along saidgirder, each of said strut members being formed of an integral rod andhaving the shape of a closed triangle with the tip of the trianglewelded to the lower chord and with the base of the triangle extendingtransverse to the longitudinal directionV of the upper chord and weldedto the lower side thereof so that the upper' surface' of said base islocated in a plane lower than the top surface of the respective adjacentportions of the longitudinally extending rods of said upper chordwhereby the longitudinally extending rods of said upper chord form siderails for said base, said triangular strut members being located inplanes respectively arranged perpendicular to both said upper chord andsaid lower chord; a plurality of stay members alternating with saidstrut members, each stay member being formed of an integral 'rodcomprising a cross piece transverse to the longitudinal direction of thegirder and arranged below and Welded to the longitudinally extendingrods of said upper chord, each stay member also comprising two diagonalportions respectively extending from the ends of said cross piece inopposite directions with regard to the longitudinal direction of thegirder, the free ends of said diagonal portions being welded to saidlower chord at the tips of adjacent struts, and a wooden hattenpositioned between said rods of said upper chord and secured to thoseportions of the triangle-shaped strut members which extend between thelongitudinal rods of the upper chord, said batten also being secured tothose portions of the cross pieces of said stay members which arelocated between the longitudinal rods of said upper chord.

5. A welded lattice girder of triangular crossV section which'comprisesin combination: anvupper chord having two longitudinally extending rodsof substantially circular cross section; a lower chord comprising asingle longitudinally extending rod of substantiallyV circular crosssection; a plurality of strut members spaced longitudinally along saidgirder,` each of said stint members being formed of an integral rod 4andhaving the shape of a closed triangle with the tip of the trianglewelded to the lowerchord and with the base of the triangle extendingtransverse to the longitudinal direction of the upper chord and belowthe latter while being welded thereto, said triangular strut membersbeing located in planes respectively arranged perpendicular to both saidupper chord and said lower4 chord; a plurality of stay membersalternating with said strut members, each stay member being formed of anintegral rod and comprising a cross piece transverse to the longitudinaldirection of the girder and extending below the upper chord while beingwelded thereto, each stay member also comprising two diagonalportions-respectively extending from the ends of said cross piece inopposite directions with regard to the longitudinal direction of thegirder, the free ends of said diagonal portions being welded to thelower chord at the tips of said two struts, and two connecting membersrespectively arranged at each end of said girder and respectivelyconnecting the ends of saidupper chord with the endsof said lower chord,at least one end of said Vgirder being provided with a hinge-like sleeveextending from one side of said-girder to substantially the centrallongitudinal plane thereof.

(References onV following`- page) References Cited in the le of thispatent UNITED STATES PATENTS Paurat June 12, 1956 McDonald Oct. 8, 19575 6 Y Great Britain May 20, 1948 Great Britain Dec. 10, 1948 GermanyNov. 22, 1951 Germany Sept. 3, 1953 Germany Sept. 24, 1953 Great BritainNov. 10, 1954

